As the UK file-sharing debate reaches fever pitch, with opinionated artists being shipped in by the bus load to condemn it, inevitably attention is turning to the costs associated with trying to end it. According to a boss at ISP BT, not only are the government's plans doomed to fail, but could end up costing ISPs a staggering £1m a day.

As Lily Allen leads a procession of artists showing a united front against online music piracy and calls ever louder for the government to do something about it, the cold light of day has kicked in. Just how much is the hoped-for crackdown on illicit file-sharers going to cost?

Yesterday, speaking with the UK’s The Mirror, John Petter, boss of ISP BT’s consumer division, said that measures to tackle Internet piracy will be costly.

Noting that ISP profit margins are already small, Petter said he fears that the process could cost ISPs a staggering £365m a year.

However, according to Jupiter Reseach, whose figures the BPI uses when trying to convince others how much money they lose, the British music industry will lose £200m worth of business to online piracy in 2009.

If the BPI’s ‘losses’ figures are to be believed (and we have to go along with the ridiculous premise of 1 download = 1 lost sale in order to do so), saving £200m worth of business will end up costing ISPs almost double that amount.

“Their [music industry] claims are melodramatic and assume people would buy all the music that is illegally downloaded, which is nonsense,” said Petter, adding that laws are already in place to deal with illicit file-sharing, but the industry doesn’t want to use those particular ones because it would hurt their public image.

Petter’s final point is possibly the most important one. He believes that the war against file-sharing will lead to a technological arms race as Internet users find new ways to hide their activities.

Indeed, by spending a measly £3.00 per month on a cheapo VPN service from the likes of SwissVPN, it’s possible for any user to tunnel right out of the UK and no-one in the country will have a clue what they are doing on their connection. Not the BPI, not ISPs, not the government.

That’s around 10p per day to defeat a £1m a day system that isn’t even in place yet. Something doesn’t add up.